Brine, which is a combination of rock salt and water in an aqueous solution containing between 23% and 26% salt, is used for treating roadways during winter storms. When applied before the storm, brine can provide an anti-icing layer that prevents a bonding between the roadway and ice, facilitating ice and snow removal. The use of brine can often reduce the use of salt and sand, lessening environmental damage, and because it can be applied before the storm, may reduce labor costs by allowing road treatment during regular business hours.
Brine is currently prepared in tanks with open tops through which salt may be loaded. The salt is supported above the bottom of the tank by horizontal screens. Nozzles about the upper lip of the tank may then be used to spray water over the surface of the salt, the latter of which may percolate downward through the screens into the lower portion of the tank. The water may be collected at the bottom of the tank and recirculated one or more times through a second set of nozzles until the desired salinity is obtained. An example of this design is taught by U.S. Pat. No. 7,810,987, which issued on Oct. 12, 2010.
As noted in the above cited patent, the salt is often contaminated with dirt and silica which can be abrasive and can cause excess wear on pumps, flow meters, and valves in the delivery chain of the brine. Accordingly, these contaminants are allowed to settle in the tank at a point below the brine outlet. Cleaning the sediment from the tank can be facilitated by sloping the tank bottom to a sump channel leading to a sediment outlet in the tank. In use, the tank is drained (possibly without removal of the salt) and spray nozzles are used to force the sediment through the channel and out the sediment outlet.
Obtaining the necessary salinity using such systems can be significantly delayed by the time it takes to recirculate the brine for multiple passes through the salt. Cleaning the sediment from the tank is time-consuming and requires that the machine be drained and thus remain off-line for a significant period of time. Substantial sediment may accumulate in a few hours of operation, thus significantly affecting the throughput of the device.